Nearby Freeways Affect Kids' Lungs

Jan. 25, 2007 -- Children living close to freeways may have slower lung
development between ages 10 and 18 than those living farther away.

That's according to a study of more than 3,000 southern California children,
published in The Lancet's online edition.

"Since lung development is nearly complete by age 18 years, an
individual with a deficit at this time will probably continue to have less than
healthy lung function for the remainder of his or her life," write
researcher W. James Gauderman, PhD, and colleagues.

The study may raise "important questions for society about the structure
of the transportation system, engines, fuels, combustion, and road dust in
urban areas," editorialists write in The Lancet.

About the Study

Gauderman works in the University of Southern California's preventive
medicine department.

He and his team studied 3,677 children in 12 communities in southern
California.

The children were in the fourth grade (average age: 10 years) when the study
started in the 1990s. They took yearly lung function tests for up to eight
years.

Children 10 to 18 go through a period of rapid lung development, the
researchers note.

The researchers also looked at how close the children lived to freeways and
found that 440 lived less than a third of a mile from one.

Their results showed that the children living that close to a freeway had
slower lung development during the study, compared with those living at least
three times farther from a freeway.

The findings held after the researchers took other factors into account,
including family income, race, asthma, smoking, regional air quality, and kids
who moved during the study.

Local roads that weren't freeways were not associated with slower lung
development.

The children weren't followed beyond age 18, so it's not clear how well
their lungs functioned later in life.

Freeway Pollution the Problem?

The concentration of pollutants in the area near major freeways may be the
problem, but it's hard to rule out other influences, note Gauderman and
colleagues.

It's also not clear what factors, if any, influenced the kids' lung
development before age 10, say the editorialists. They included Thomas
Sandstrom, MD, PhD, of the respiratory medicine and allergy department of
University Hospital in Umea, Sweden.

"However, these questions should not distract from the major achievement
of follow-up of such a large group of children through secondary school with
repeated lung function tests," write the editorialists.

The study was funded in part by the California Air Resources Board, the
National Institute of Environmental Health Sciences, and the Environmental
Protection Agency.